Mobile telecommunications network users have a “home” network. The home network is the network with which the user is generally permanently registered and with which the user has a contract or other mechanism for paying for services. “Roaming” in other mobile telecommunications networks is permitted when those other telecommunications networks have an agreement with the home telecommunications network.
It is a long term problem for telecommunication network operations that traffic originated from various countries and networks to the home network or to domestic networks is deflected from the normal route to a much cheaper, but lower quality route (e.g. Voice over Internet Protocol, VoIP) without the knowledge of the originating or terminating network operator. In such cases, it is quite typical, that the traffic is routed to a PBX for which so called SIM-boxes (mobile equipments with SIM cards) are connected in order to terminate traffic via the SIM-boxes to the terminating network. This kind of call termination causes a lot of problems and financial loss to the operators. The most important problem is the financial loss (difference between the terminating fee and the minute fee of the SIM-box, cost for extra capacity required by SIM-boxes, etc.). The problems also include unsuccessful calls to roamers and unsuccessful calls from CAMEL roamers from abroad resulting in lost revenue and customer dissatisfaction.
Current methods used to detect SIM-boxes are unsatisfactory. These methods include call behaviour analysis, but this has the main problem that it does not prove SIM-box usage. Another known method is to generate a test call originated from abroad by third parties to the tested network, but this results in extra cost for the operator. It should be noted that the latter method relies on the presentation of the calling line identity (CLI) to the terminating test number in order to recognize SIM-boxes. Since SIM-boxes usually hide their MSISDN, the MSISDN of the SIM-boxes can be detected by the third party if the CLIP override (Calling Line Identity Presentation override) feature is activated for the terminating SIM. In countries in which the handling of CLI is regulated (e.g. for data protection reasons CLIP override should be activated only in certain cases defined by the law) the usage of this method may be illegal. Neither call behaviour analysis, nor third party test call generation are able to detect SIM-boxes from blocked unsuccessful calls attempts and are incapable of measuring the number of blocked (unsuccessful) calls caused by SIM-boxes in the international communication path. Moreover, none of these methods can be used by the originating network to measure international call paths from the originating network to other foreign mobile networks.
Accordingly, it would be desirable to provide an improved arrangement to identify mis-routed international calls, such as those diverted to SIM-boxes.